Lamp socket adapter



Oct. 5, 1954 e, R. LAWSON LAMP SOCKET ADAPTER Filed Feb. 19, 1954inventor: Guszfaf RLau/s Q9 WK ms A aom Patented Oct. 5, 1954 UNITEDS'EA'Iiiiii PATENT ()FFICE LAMP SGCKET ADAPTER New York ApplicationFebruary 19, 1954:, Serial No. 411,337

6 Claims.

The present invention relates to an adapter which may be installed in anelectric socket so that a smaller size lamp than the lamp for which thesocket was designed may be mounted in the socket. This inventionpertains more particularly to a lamp socket adapter for use withphotofiash lamps such as are employed in photography, although it shouldbe appreciated that the invention is not restricted in its use to flashlamps and flash attachments.

One of the limitations of flash photography in the past has been thenecessity of carrying bulky equipment in the form of a flash attachmentand a quantity of flash lamps in addition to the camera. Photoflashlamps have a burning life of only a few hundredths of a second;therefore, they must be replaced after the taking of each picture. Itbecomes very cumbersome to carry eight or twelve flash lamps for eachroll of film.

Recently there has been developed a new and improved flash lamp which isof a smaller size than those heretofore available on the market. Thisnew flash lamp is similar in size to the smallest Christmas tree lampand about onehalf of the size of its immediate forerunners. With thisundersized lamp, it will be relatively easy to carry eight or twelve ofthese new lamps because they take up such little space. This new lampdevelopment makes possible for the first time the construction of morecompact flash attachments than have been previously available on themarket. Since these new flash lamps are of reduced size, they do not fitthe lamp sockets of the present day flash attachment equipment.Therefore, new flash units to accommodate the new lamps must be designedfor the future, while adapters will have to be used for fitting thesmaller size lamps into the lamp socket openings of the flashattachments now in use.

Accordingly, the principal object of this invention is to provide anadapter for a lamp socket so that an undersized lamp may be mounted inthe socket.

A further object is to provide a readily removable lamp socket adapterfor flash attachments used in photography so that two diflerent sizes offlash lamps may be used alternatively in the same flash attachment.

A further object is to provide a novel lamp socket adapter having acoiled spring contact means.

A further object is to provide in a lamp socket a novel coiled springcontact means.

A further object is to provide an improved 2 method of installing aspring in an apertured wall.

A still further object is to provide in a lamp socket or socket adaptera trigger mechanism for cooperation with a lamp to hold it in place andto release it from the socket or the adapter, as the case may be.

The present invention as herein described is embodied in one instance ina lamp socket adapt er comprising an outer metal shell adapted forinsertion into a lamp socket, the shell being open at one end andprovided with an aperture at its opposite end. Within this shell ismounted a cup-shaped insert of insulating material. This insert is openat its outer end to receive a lamp base therein. There is an aperture inthe inner end of the insertwhich is in alignment with the aperture inthe shell. A coiled compression spring having a reduced central portionlocated within the said apertures is provided in adapter so that itserves the multiple function of carrying current, of making goodelectrical contact with the live contact of the existing flashequipment, and also of providing the ejecting means for the spent flashlamp. A trigger is also located within the adapter to engage the base ofthe flash lamp for making electrical contact with it and for locking thelamp in position. The free end of the trigger extends outwardly of theadapter and is used as a lever to disengage the trigger from contactwith the lamp.

This invention also includes a novel method of inserting the coiledcompression spring in an aperture such as the aperture through the baseof the adapter. duced central portion and large outer ends, one endbeing axially open and the other end being substantially closed. Toinsert the spring into an aperture which is smaller than both ends ofthe spring, the spring is located in the adapter with its closed end atthe entrance to the aperture, and a rod is thrust into the open outerend of the spring until the end of the rod engages the opposite closedend of the spring. By applying a pushing force with the rod, the end ofthe spring is elongated thereby reducing its diameter, so that the turnsof the spring will thread their way through the aperture until thecentral portion of the spring is confined within the aperture.

Likewise, the novel spring of this invention may be incorporated in alamp socket which is designed to receive the undersized lamps. The loweror back wall of the socket is similar in design to the lower orapertured wall of the insert of the socket adapter.

The coiled spring has a re My invention will be better understood fromthe following description taken in connection with the accompanyingdrawing, and its scope will be pointed out in the appended claims.

In the drawing:

Fig. l is a partial sectional elevational view of the complete lampsocket adapter embodying my invention with a lamp mounted therein.

Fig. 2 is a top plan view of the lam socket adapter of Fig. l with thelamp removed.

Fig. 3 is a sectional view of the insert taken generally on the line 33of Fig. 2 ShOWing how the spring of this invention is positioned withinthe insert of the adapter before the spring is forced through theaperture in the end of the insert and confined therein.

Fig. 4 is a sectional view similar to Fig. 3 show ing how a rod is usedto elongate one end of the spring to temporarily reduce its diameter sothat i it may slip through the aperture in the insert.

Fig. 5 is an exploded view of the socket adapter of Fig. l'with the lampremoved.

Fig. 6 is a partial cross-sectional view of a combined lamp socket andreflector for a flash attachment.

Referring in detail to the drawing, 10 represents the metal shell of alamp socket adapter which is similar in size and shape to the bayonetbase of the flash lamps now available on the market, whereby the adaptercan readily be inserted into existing sockets for such lamps. This shellI9 is provided with a pair of oppositely disposed bayonet pins orprotrusions l l which are used to cooperate with the lamp socket of aflash attachment to guide and hold the adapter therein. The shell IE) isprovided with an aperture I2 in' its base portion. Mounted within theshell is a cupshaped insert l3 of insulating material which is providedat one end with an outer boss 14 that is seated in the aperture l2 ofthe shell. The boss I4 has a centrally disposedaperture l5 communicatingwith the inner compartment of the insert. The upper end of the shell 10as well as the upper end of the insert [3 are open to accommodate thelamp base I6 of a lamp I! therein.

A coiled copper wire spring I 8 is mounted within the adapter to providean ejecting means for a lamp that is to be removed, and also to carrycurrent as the center contact of the adapter for making electricalconnection with the center contact at the base of a lamp. The spring I8is of novel design, the two ends of the spring being. both larger indiameter than the center portion. The center portion [9 of the springcomprises a plurality of turns of equal diameter, which turns areclosely wound so that when the lamp is inserted in the adapter and theadapter in the socket of a flash attachment, there is no spring actionin said portion. The lower end of the spring presents a shoulder 2| ofone or more turns of larger diameter than the diameter of the aperturel5 through the bottom of the insert. The end 20 of the spring is alsotapered from the shoulder portion 2| to a reduced end section 22 whichis substantially closed. The opposite end 23 of the spring has spacedturnsat a greater pitch than the turns of the remainder of the spring.The reason for this is that the portion 23 of the spring is designed tobe compressed when a lamp I! is forced into the adapter so that thespring portion 23 stands ready to act as the ejecting means for thelamp.

Turning now to Fig. 3 and Fig. 4 of the drawing, the novel method ofthis invention of locating the spring IS in the adapter will becomeapparent. The spring I8 is first placed over the aperture [5 in theinsert [3 with the short tapered end 28 located partially within theaperture. A short length of rod 2 of a diameter in the order of about {aof an inch is next inserted through the spring at the end portion 23until the end of the rod is seated on the closed end section 22 of thespring. In order to facilitate the following operation, the upper edge25 of the aperture I5 is countersunk. When a force is directed down onthe rod 24, the tapered end 20 of the spring will begin to elongate asis seen in Fig. 4, thereby reducing the diameter of the end portion 20until the eifective size of the shoulder 2| of the spring is smallerthan the aperture I5 in the insert. When the diameter of the end portion20 of the spring is so reduced, the pushing force supplied by the rod 2Ato the end section 22 of the spring forces the spring to move throughthe aperture until the large portion 23 of the spring engages the baseportion of the insert. Thus, the center portion [9 is locked or confinedwithin the aperture as is shown in Fig. l, for when the rod iswithdrawn, the end portion 20 of the spring returns to its originalshape. When the spring is located within the aperture, it, in effect,constitutes two springs. The inner portion 23 of the spring acts as anelectrical contact for a lamp as well as the ejecting means to dischargethe lamp after it has been used, while the outer end 20 of the spring isadapted to make good electrical contact with the live contact of theflash attachment.

In order to hold the flash lamp H in the adapter, a trigger 26 is used.The lower end 2? of the trigger is positioned in a recess 9 in the outersurface of the insert I3 and in contact with the inner surface of theshell Ill. The central portion of the trigger 26 is normally biasedinwardly of the adapter and is provided with a latch portion which maybe a lancing or a rivet means for engagement with the base of the lampH. The lamp base i6 of the lamp I1 is provided with a circumferentialgroove 29 in place of the usual bayonet pins or screw threads.Accordingly, it is not necessary to accurately position the flash lamprelative to the slots in the socket, nor is it necessary to screw thelamp into the lamp socket. The cup-shaped insert l3 has an outer bore ofa diameter to accommodate the base of a lamp as well as an inner bore 4|of reduced cross-section. There is a shoulder or circular ledge 42joining the large bore 40 with the smaller bore 4|. This ledge 42 is solocated that it serves as a stop means for the inward movement of thelamp. As a result of this arrangement, the groove 29 of the lamp basecannot move inwardly past the latch portion 30 of the trigger. Withoutthis limiting feature, it might be possible to use a lamp to compressthe end portion 23 of the spring to its maximum amount while at the sametime moving the groove 29 of the lamp base inwardly and beyond the latchportion 39 of the trigger. If the downward force on the lamp werequickly released, the force of the spring might be strong enough toeject the lamp before the trigger could snap back to engage with thequickly moving lamp base.

To install the flash lamp I1, it is merely necessary to push the lampinto the socket adapter against the action of the end portion 23 of thespring I8 until the trigger engages with the circumferential groove 29to lock the lamp in place. There is a vertically extending slot 3| inthe upper wall of the insert i 3 so that the lower portion 21 of thetrigger 26 is located between the insert it and the shell it], while thecenter portion of the trigger containing the latch 30 extends throughthe said slot 3! to engage the lamp base it. From the center portion ofthe trigger to its outer end, the trigger is located in the said slot 3iuntil it emerges from the shell l and extends at an angle so that itdoes not interfere with the flash lamp H. The rim 28 of the shell I!) isturned over as the final assembly operation to hold the insert firmlywithin the shell I0. As can be seen in Fig. 2, this rim 28 is not turnedover in the area directly under the trigger as it emerges from the shellHi. This is so because the travel of the trigger would be hamperedunless sumcient clearance were made at this point.

The method of assembling the lamp socket adapter embodying thisinvention is simple and economical and easy to perform on a massproduction basis. First, the compression spring it must be locatedwithin the insert i3 with the tapered end 25 of the spring positioned inthe aperture [5. The rod 2 3 is thrust through the spring it until theend or" the rod engages the closed section 22 of the spring. A pushingforce is applied to the rod 2 3 which elongates the end 25 of thespring, thereby reducing its eflective diameter as well as threads thelarge turns of the shoulder it through the aperture l5 until the centralportion I9 of the spring is seated within the aperture. Then the trigger26 is placed with its end portion 2i resting on the bottom wall of theshell it so that the insert it may be placed within shell it with thehollow bore I l extending through the aperture l2 of the shell. The rim28 of the shell i9 is then turned over in the final assembly step so asto hold the parts together. The socket adapter is then ready for use.

The flash lamp ll is mounted in the socket adapter by merely pushing itinto the interior of the adapter against the action of the spring untilthe latch is of the trigger 25 engages in the groove 29 of the lamp base16. The socket adapter embodying my invention remains a permanent partof any flash attachment as long as these new and improved smaller sizeflash lamps are to be used. To withdraw the adapter from the flashattachment, it is merely necessary to disconnect it in the same manneras if it were one of the flash lamps designed for the flash attachment.Therefore, with this invention, it is possible to use either the sizelamps which were designed for the flash attachment or it is possible toinstall this socket adapter and take advantage of the convenience andlow cost of the smaller size flash lamp.

As will be noted in the exploded view of the socket adapter of Fig. 5,the lower end 21 of the trigger 25 is formed at an acute angle. When thetrigger is placed in the adapter, the insert 13 acts against the lowerportion Zl to enlarge the acute angle so that it is substantially aright angle. The insert it is assisted in holding the trigger in thisrelation by the rim 28 of the shell it which is turned over as the finalassembly operation. Because the trigger is stressed in this manner, itis normally biased inwardly of the large bore 40 of the insert [3.Consequently, it will always be in position to engage with the groove 29of the lamp base 16.

Fig. 6 of the drawing illustrates a combined lamp socket and reflectorwhich has been designed to receive the undersized lamps. In this view isshown lamp socket 5!], reflector 5|, flash lamp 52, and center contact53, as well as the outer contact 54. The novel spring 55 is mounted inthe apertured wall 56 of the socket to connect the center contact 53with the center of the lamp 52. A trigger 5'! is fastened in the socketto connect the outer contact 54 with the side of the lamp base of thelamp 52. The spring 55 is mounted in the socket 50 in the same manner asthe spring I 8 is inserted in the insert it of the above-mentionedsocket adapter. Also, the cooperation between the lamp 52 with thespring 55 and trigger 51 is substantially the same as is found betweenthe same parts of the socket adapter. In order to insert the trigger inthe socket and to hold it in place, the hooked end 58 of the trigger islocated within a complemental slot in the socket. Then the outer contact54 is slipped between the trigger and the opposite wall 59 to wedge thelower end of the trigger 5! in place.

Consequently, having described my invention of a novel lamp socket andlamp socket adapter, it will be readily apparent to those skilled inthis art that I have constructed a socket and socket adapter which havea minimum number of parts, which are simple in design and easy tomanufacture as well as easy to assemble with a minimum amount of handlabor.

Modifications of this invention will occur to those skilled in the art,and it is to be understood, therefore, that this invention is notlimited to the particular embodiment disclosed but that it is intendedto cover all modifications which are within the true spirit and scope ofthis invention.

What I claim as new and desire to secure by Letters Patent in the UnitedStates Patent Ofiice 1. A lamp socket adapter comprising an outer shellof conductive material for insertion into a lamp socket, the shell beingopen at one end, and provided with an aperture at its opposite end, ahollow insert of insulating material fixed within the shell, said insertbeing provided with an apertured boss extending through the aperture insaid shell, a compression spring located within the insert with thecenter portion of the spring extending through the said boss, the endsof said spring being larger than its center portion so that the springis confined within said boss.

2. A lamp socket adapter comprising an outer metal shell for insertioninto a lamp socket, the shell being open at one end and provided with anaperture at its opposite end, a hollow insert of insulating materialmounted within the shell, said insert being provided with an aperturedboss extending through the aperture in the shell, a coiled compressionspring confined within the said boss, a trigger member fixed at itsinner end between the shell and the insert with its outer end projectingto the outside of said assembly, the said trigger being adapted toreleasably engage a lamp base mounted in the adapter.

3. A lamp socket adapter for flash lamps comprising an outer metal shellthat is provided with a pair of oppositely disposed bayonet pins on itsouter surface, the shell being open at one end and provided with anaperture at its opposite end, a hollow insert of insulating materialmounted within the shell, said insert being open at its outer end toreceive a lamp base therein, the insert being provided with an aperturedboss extending through the aperture in the shell, a coil spring having areduced central portion located within the said boss, the ends of saidspring being enlar'ged to confinethe-springtherein so that the springserves as the center contact for said adapter, a resilient triggermember fixed at its inner end between the shell and the insert with aportion of the trigger extending through a slot in the-walls of theinsert to releasably engage a lamp base, the free end of the triggerextending to the outside of said adapter;

4. A lamp socket device comprising a hollow, lamp receiving housing openat one end and having an apertured Wall at its opposite end, acornpressible, coiled contact spring having a central portion of reduceddiameter positioned Within said aperture, the ends of the spring on bothsides of the aperture being enlarged to confine the spring within theaperture, and releasable means within the housing for engaging a lampbase therein and making electrical contact therewith.

5. The method of mounting in an aperture a coil spring having a reducedcentral portion and enlarged outer ends, comprising the steps ofthrusting a rod through one end of the spring until the endof the rodengages the opposite endof the spring, of placing the end of the springagainst the said aperture and applying a force on the rod to elongatethe end of the spring thereby reducing its effective diameter so that itslips into place with the central portion of the spring confined withinthe said aperture.

6. In a lamp socket adapter as recited in claim 1, a resilient triggermember fixed thereon with an inwardly extending latch portion forreleasab-ly engaging a lamp base, and an outwardly extending free endportion which is adapted to be manually operated to release the lamp.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,316,231 Evans Apr. 13, 1943 2,457,930 Smith Jan. 4, 19492,462,530 Miller Feb. 22, 1949 2,565,492 French Aug. 28, 1951 2,578,296Ernisse Dec. 11, 1951 2,602,879 Whelan July 8, 1952

